With rapid development of wireless communications technologies, a transmission capacity in microwave point-to-point communication continuously increases, and an E-band (71 to 76 GHz, 81 to 86 GHz) frequency band microwave device plays an increasingly important role in a base station backhaul network. However, because “rain fade” on an E-band frequency band electromagnetic wave is extremely severe, an E-band microwave single-hop distance is usually less than 3 kilometers. To increase the E-band microwave single-hop distance and reduce site deployment costs, a solution is provided, in which the E-band frequency band microwave device and another low frequency microwave device are cooperatively used. When there is relatively heavy rain, even if the E-band microwave device cannot normally work, the low frequency microwave device can still normally work.
A dual-band parabolic antenna is used in this solution, and a structure is shown in FIG. 1. The dual-band parabolic antenna includes a primary reflector, a secondary reflector, a low frequency feed, and a high frequency feed. Both the low frequency feed and the high frequency feed are a type of horn antenna, and are usually referred to as a horn feed when being applied to another antenna structure. The two feeds share the primary reflector. A frequency selective surface (, FSS) is used as the secondary reflector. The secondary reflector is designed as a hyperboloid, a virtual focus of the hyperboloid and a real focus of the primary reflector are overlapped, and the feeds of different frequencies are respectively disposed at the virtual focus and a real focus of the hyperboloid. The secondary reflector transmits an electromagnetic wave transmitted by the low frequency feed located at the virtual focus, and reflects an electromagnetic wave transmitted by the high frequency feed located at the real focus, so as to implement a dual-band multiplexing function.
In the prior art, a low frequency horn feed and an FSS are two independent components. Therefore, there are problems that a large assembly error exists, an antenna gain is low, and a beam direction deviates from a boresight axis direction.